Bottom processing

ABSTRACT

Embodiments disclosed herein generally relate to methods and apparatus for processing of the bottom surface of a substrate to counteract thermal stresses thereon. Correcting strains are applied to the bottom surface of the substrate which compensate for undesirable strains and distortions on the top surface of the substrate. Specifically designed films may be formed on the back side of the substrate by any combination of deposition, implant, thermal treatment, and etching to create strains that compensate for unwanted distortions of the substrate. In some embodiments, localized strains may be introduced by locally altering the hydrogen content of a silicon nitride film or a carbon film, among other techniques. Structures may be formed by printing, lithography, or self-assembly techniques. Treatment of the layers of film is determined by the stress map desired and includes annealing, implanting, melting, or other thermal treatments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationNo. 62/306,150, filed Mar. 10, 2016, the entirety of which is hereinincorporated by reference.

FIELD

Embodiments of the present disclosure generally relate to methods andapparatus for semiconductor processing. More specifically, embodimentsdescribed herein relate to methods and apparatus for processing a bottomside of a substrate.

BACKGROUND

During chip manufacturing, substrates experience non-uniform localizeddistortions which, if uncorrected, cause misalignments of lithographypatterns between layers. The registration may be corrected for certaintypes of distortions in that the pattern can be optically matched duringthe lithography print. For other types of distortions, however,correction is not possible and a yield loss results. Furthermore, asfeature sizes continue to shrink, the tolerance to distortions decreasesand the number of uncorrectable distortions increases.

Distortions have previously been corrected for via the localimplantation of controlled amounts of ions into the hardmask to createlocal strains. The local strains compensate the previously existingones. However, contamination of the underlying layers by the chosen ionis possible.

Other attempts to correct for distortions involve variable local surfaceannealing of the hardmask to create local strains which compensate thepreviously existing ones. One the other hand, however, partialrelaxation occurs as the surface of the hardmask is removed duringsubsequent processing.

Therefore, what is needed in the art is a method and apparatus fortreating the backside of a substrate.

SUMMARY

In one embodiment, a method for treating a backside of a substrate isdisclosed. The method includes depositing a film on the backside of thesubstrate, annealing the substrate, and implanting on the backside ofthe substrate. The method further includes thermally treating thebackside of the substrate.

In another embodiment, a method for treating a backside of a substrateis disclosed. The method includes annealing the substrate, implantingthe backside of the substrate, and thermally treating the backside ofthe substrate. The method further includes etching the backside of thesubstrate, and aligning the substrate for patterning.

In yet another embodiment, a tool for processing a substrate isdisclosed. The tool includes a process chamber for depositing aplurality of film layers on a backside of the substrate. The processchamber includes a transfer chamber, a deposition tool, an annealingtool, and an etching tool. The annealing tool anneals the plurality offilm layers on the backside of the substrate and includes a substrateedge support. The etching tool etches the backside of the substrate andincludes a substrate edge support.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 schematically illustrates operations of a method for treating abackside of a substrate, according to one embodiment.

FIG. 2 schematically illustrates operations of a method for treating abackside of a substrate, according to one embodiment.

FIG. 3 illustrates a schematic diagram of a deposition chamber,according to one embodiment.

FIG. 4 illustrates a schematic isometric view of an apparatus forthermally processing a substrate, according to one embodiment.

FIG. 5 illustrates a schematic isometric view of a rapid thermalprocessing chamber for thermally processing a substrate, according toone embodiment.

FIG. 6 illustrates a schematic diagram of an apparatus for thermallyprocessing a substrate, according to one embodiment.

FIG. 7 illustrates a schematic diagram of an etch reactor, according toone embodiment.

FIG. 8 illustrates a top schematic view of a cluster tool transferchamber having a plurality of substrate processing chambers, accordingto one embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments disclosed herein generally relate to methods and apparatusfor processing of the bottom surface of a substrate to counteractthermal stresses thereon. Correcting strains are applied to the bottomsurface of the substrate which compensate for undesirable strains anddistortions on the top surface of the substrate. Specifically designedfilms may be formed on the back side of the substrate by any combinationof deposition, implant, thermal treatment, and etching to create strainsthat compensate for unwanted distortions of the substrate. In someembodiments, localized strains may be introduced by locally altering thehydrogen content of a silicon nitride film or a carbon film, among othertechniques. Structures may be formed by printing, lithography, orself-assembly techniques. Treatment of the layers of film is determinedby the stress map desired and includes annealing, implanting, melting,or other thermal treatments.

As utilized herein a substrate is any suitable substrate, such as asingle crystal silicon substrate; silicon on insulator (SOI); SiliconGermanium or alloys thereof, glass or quartz substrate with a siliconlayer thereon, as used for manufacturing thin film transistors (TFT); orthe like. The substrate may have devices and structures formed on adevice side of the substrate.

FIG. 1 illustrates operations of a method 100 for treating a backside ofa substrate to compensate for strains on the front side of thesubstrate.

At operation 110, a film is deposited on the backside of the substrate.The deposition may be completed utilizing any PRODUCER® series chambercommercially available from Applied Materials, Inc. located in SantaClara, Calif. In some embodiments, the film may be a blanket filmdeposited on the backside of the substrate. The film may be, or include,an amorphous carbon film, a silicon oxide film, or a silicon nitridefilm.

An area of the film is deposited to a corresponding area of thesubstrate. The film may be deposited on a backside of the substrate. Incertain embodiments, the area of the film corresponds to a die on afront side of the substrate. The film may be deposited to a thickness ofbetween about 40 nanometers and about 120 nanometers. In certainembodiments, the film may be deposited to an edge of the substrate.

A layer of different or varying thicknesses may be formed on thebackside of the substrate using standard patterning techniques known inthe art. Therefore, when annealing the film layer different stresses maybe created. For example, in some embodiments, a blanket film layer maybe deposited on the backside of the substrate, and a mask may be used toselectively deposit additional film in desired locations. The stress inthe blanket film and the additional film may be selected and applied byadjusting processing conditions.

For example, an amorphous carbon layer may be deposited on the backsideof the substrate. A silicon oxide layer may be deposited on theamorphous carbon layer. The silicon oxide layer may be patterned to forma mask, and then a second amorphous carbon layer may be deposited overthe substrate. The substrate may be planarized on the back side toexpose the silicon oxide mask, which may then be removed to leave anamorphous carbon layer having selectively varying thickness.

At operation 120, the backside of the substrate is annealed. Theannealing changes the structure of the back side film and adjustsstrains in the film according to any desired pattern. For example,annealing may relax strains in the film as deposited. The film may beselectively locally annealed to produce correcting strains on thebackside of the substrate which compensate for undesirable strains on afront side of the substrate. The film may also be blanket annealed inone step, in some embodiments, to adjust strains selectively added tothe film during deposition. The correcting strains are produced in oneembodiment by applying designed film layers to the backside of thesubstrate. The correcting strains are produced in another embodiment viathe utilization of film layers already present from a previousprocessing.

In some embodiments, the annealing is spot annealing. The spot annealingoccurs on select locations of the backside of the substrate. Theannealing operation may utilize various types of energy. In someembodiments, the annealing is a nanosecond annealing process. In otherembodiments, the annealing is a millisecond annealing process.

The annealing results in a change to the desired layer on the backsideof the substrate that may be used to relieve stresses and/or strains inthe layer as deposited. Selectively relieving the stress and/or strainmay create a pattern of stress in the substrate to compensate forstructural non-uniformities resulting from the thermal processing. Astress state of the overall substrate may change during the annealingprocess, so the annealing process may be designed to produce anintermediate stress/strain state of the substrate that is furtherchanged by subsequent processing.

In some embodiments, a plurality of zones may be defined on the backsideof the substrate, and each zone may be annealed using different processconditions. For example, a first zone may be annealed via a nanosecondannealing process, and a second zone may be annealed via a millisecondannealing process. In another embodiment, layers of material may beselectively deposited on the backside of the substrate. For example,amorphous carbon may be deposited on a first layer while other layersare coated with silicon dioxide.

At operation 130, the backside of the substrate is implanted. Theimplant may be completed utilizing any VIISTA® chambers commerciallyavailable from Applied Materials, Inc., located in Santa Clara, Calif.Implanting is another way to adjust stress in the back side film byadding dopants. A class of films that may be utilized in the presentdisclosure includes Advanced Patterning Films (APF) which includeamorphous carbons. As such, a doped amorphous carbon may be deposited, aplain amorphous carbon may be deposited, or a plain amorphous carbon maybe deposited and subsequently doped. The film may also comprise one ofnitrides, metal silicides, or any other material that undergoes a phasechange. In some embodiments, the film may be self-absorbing, in that thefilm dissolves, reacts with, and/or diffuses into the substrate.

The implanted dopant may be selected to adjust stress in the depositedlayer. The dopant may be implanted according to a pattern in order tomodify stress in specific areas of the film. The stress may be a tensilestress and/or a compressive stress. The dopants may be metals ornon-metals. Dopants may include He, Ne, Ar, F, Cl, Br, O, N, P, As, Si,Ge, Sn, B, Al, Ga, In, Zn, Cu, Ag, Au, Ni, Ti, and combinations oralloys thereof.

The implant may be performed by ion beam or plasma. In some embodiments,the implant may be a direct implant. In other embodiments, the implantmay be a deposition followed by diffusion. In some cases, a cappinglayer may be used during a diffusion implant process.

In various embodiments, the backside of the substrate is etched. An etchchamber, described infra, may etch the backside of the substrate. Theetch process may proceed according to a desired pattern, using a mask orother pattern feature, to affect stress throughout the substrate byapplying a patterned stress differential to the backside of thesubstrate. The etch process may also be a blanket removal of materialfrom the backside of the substrate to apply a blanket stressdifferential to the backside of the substrate. A blanket stressdifferential may be effective to change the overall local stress in onepart of the substrate more than in another part of the substrate, whichmay be useful for some embodiments.

In various embodiments, patterns of stress may be formed on the backsideof the substrate to compensate for strains on a front side of thesubstrate. In some embodiments, a film layer may be deposited on thebackside of the substrate, wherein the film layer, such as an amorphouscarbon, maintains a certain as deposited stress, either compressive ortensile. The film layer deposited may be annealed in selective locationsto relieve the stress.

In another embodiment, amorphous carbon may be deposited on the backsideof the substrate and selectively implanted. Subsequently, the substratemay be annealed to form a pattern which creates differing stressmatrices, thus creating patterns of stress on the backside of thesubstrate.

In another embodiment, a film layer having different thicknesses may bedeposited on the backside of the substrate. The substrate may besubsequently annealed according to a pattern, thus creating patterns ofstress on the backside of the substrate.

In another embodiment, the backside of the substrate may be etched forselective removal of the film layers, thus creating differingthicknesses and patterns of stress on the backside of the substrate.

The method 100 may also include additional operations for treating thebackside of the substrate to compensate for strains on the front side ofthe substrate. In one embodiment, the method 100 may include the localdensification of the films on the backside of the substrate. Localdensification may include locally annealing or heating the substrate ina specific area to achieve a thickness reduction in the film. Thedensification may result in an increasing refractive index. Thedensification of the substrate upon high temperature annealing may alsoimpact the electrical properties of the substrate. Annealing may furtherresult in film densification which may be prominent above thecrystallization temperature. Any change in the film properties after ahigh temperature annealing process may be independent of the depositiontechnique.

In another embodiment, the method 100 may also include the localizedetching of stressed films and/or the performance of a localized reactionbetween the film and the backside of the substrate. The operation ofperforming the localized reaction between the film and the substrate maycreate a solid product of density, thermal expansion coefficient, orother property which is different than the substrate. Furthermore, ametal film may be deposited on the substrate at a temperature whichmakes the metal film compress. After the depositing, metals, such as ametal silicide material, may be subsequently deposited on the backsideof the substrate. In some embodiments, a silicon nitride material may bedeposited on the substrate. Oxygen and/or nitrogen may further be addedto the backside of the substrate, followed by a local heating, a localimplanting, and/or a local annealing operation. In another embodiment,after providing an oxide to the backside of the substrate, an ALDoperation may be performed thereon to form a ceramic layer.

In another embodiment, the method 100 may also include the localizeddeposition of films which have a different CTE than the substrate. Inorder to take advantage of the CTE difference, the difference in stressbetween the surface of the substrate may be measured and/or controlledvia the temperature at which the depositions are made. For example,depositions made at low temperatures, such as approximately 300 degreesCelsius, may be subsequently relaxed to 100 degrees Celsius. Thedifferent CTE of the film and the substrate results in different thermalexpansions and contractions between the film or films and the substrate,which may create stresses in the substrate and/or the films across theinterface between the substrate and the films.

In another embodiment, the method 100 may also include performing alocalized reaction between the film and the substrate, thus creating asolid product having a density different than a density of thesubstrate. In some embodiments, a metal film may be deposited on thebackside of the substrate at a temperature which places a compressive ortensile force upon the metal film. Subsequently oxygen and/or nitrogenmay be added to the backside of the substrate, and, in some embodiments,an additional metal material may be added thereon. Furthermore, in someembodiments, the backside of the substrate may be locally heated,locally implanted, and/or annealed.

In another embodiment, the method 100 may also include the localizedetching of the backside of the substrate to alter the geometry affectingthe stresses thereon. The localized etching may create increase ordecrease a thickness of the matter disposed on the backside of thesubstrate, thus increasing or decreasing the stress on the substrate.

In another embodiment, the method 100 may also include annealing thebackside of the substrate to change the crystal structure, crystalorientation, and/or degree of crystallinity. In some embodiments, and byway of example only, if the crystal structure and/or orientationcomprises non-isotropic crystals, the crystal orientation may be alteredby heating the substrate in a strong electromagnetic field.

The method 100 may further include aligning the substrate forpatterning, locating distortions in the substrate, and compensating forthe distortions by flattening the substrate. In some embodiments, thesubstrate may be flattened through the use of an electrostatic chuck, aBernoulli chuck, or a vacuum chuck.

Finally, the notion of depositing as described above should beunderstood to include film formations on the backside of the substratewherein the backside of the substrate obtains a different compositionvia, by way of example only, surface reactions with gases likenitridation and/or oxidation, and/or surface implantation, among othertechniques.

FIG. 2 illustrates operations of a method 200 for treating a backside ofa substrate to compensate for strains on the front side of thesubstrate.

At operation 210, the backside of the substrate is annealed. Theannealing changes the structure of the back side film and adjustsstrains in the film according to any desired pattern. For example,annealing may relax strains in the film as deposited. The film may beselectively locally annealed to produce correcting strains on thebackside of the substrate which compensate for undesirable strains on afront side of the substrate. The film may also be blanket annealed inone step, in some embodiments, to adjust strains selectively added tothe film during deposition. The correcting strains are produced in oneembodiment by applying designed film layers to the backside of thesubstrate. The correcting strains are produced in another embodiment viathe utilization of film layers already present from a previousprocessing.

In some embodiments, the annealing is spot annealing. The spot annealingoccurs on select locations of the backside of the substrate. Theannealing operation may utilize various types of energy. In someembodiments, the annealing is a nanosecond annealing process. In otherembodiments, the annealing is a millisecond annealing process.

The annealing results in a change to the desired layer on the backsideof the substrate that may be used to relieve stresses and/or strains inthe layer as deposited, apply a desired stress differential to thebackside of the substrate, and/or change a stress profile of thesubstrate. Selectively relieving the stress and/or strain may create apattern of stress in the substrate to compensate for structuralnon-uniformities resulting from the thermal processing. A stress stateof the overall substrate may change during the annealing process, so theannealing process may be designed to produce an intermediatestress/strain state of the substrate that is further changed bysubsequent processing.

In some embodiments, a plurality of zones may be defined on the backsideof the substrate, and each zone may be annealed using different processconditions. For example, a first zone may be annealed via a nanosecondannealing process, and a second zone may be annealed via a millisecondannealing process. In another embodiment, layers of material may beselectively deposited on the backside of the substrate. For example,amorphous carbon may be deposited on a first layer while other layersare coated with silicon dioxide.

At operation 220 the backside of the substrate is implanted. The implantmay be completed utilizing any VIISTA® chambers commercially availablefrom Applied Materials, Inc., located in Santa Clara, Calif. Implantingis another way to adjust stress in the back side film by adding dopants.A class of films that may be utilized in the present disclosure includesAdvanced Patterning Films (APF) which include amorphous carbons. Assuch, a doped amorphous carbon may be deposited, a plain amorphouscarbon may be deposited, or a plain amorphous carbon may be depositedand subsequently doped. The film may also comprise one of nitrides,metal silicides, or any other material that undergoes a phase change. Insome embodiments, the film may be self-absorbing.

The implanted dopant may be selected to adjust stress in the depositedlayer. The dopant may be implanted according to a pattern in order tomodify stress in specific areas of the film. The stress may be a tensilestress and/or a compressive stress. The dopants may be metals ornon-metals. Dopants may include He, Ne, Ar, F, Cl, Br, O, N, P, As, Si,Ge, Sn, B, Al, Ga, In, Zn, Cu, Ag, Au, Ni, Ti, and combinations oralloys thereof.

The implant may be performed by ion beam or plasma. In some embodiments,the implant may be a direct implant. In other embodiments, the implantmay be a deposition followed by diffusion. In some cases, a cappinglayer may be used during a diffusion implant process.

At operation 230, the backside of the substrate is etched. An etchchamber, described infra, may etch the backside of the substrate. Atoperation 240, the substrate is aligned for patterning.

In some embodiments, the method 200 may further include depositing afilm on the backside of the substrate. A class of film may be used toadvance patterning for lithography. As such, the film comprises one ofnitrides, amorphous carbons, diamond-like carbons, metals, metalsilicides, or any other material that undergoes a phase change. In someembodiments, the film may be a metal with a stress/strain alterationarising from the formation of varying amounts of metal silicide. In someembodiments, the film is self-absorbing. An area of the film isdeposited to a corresponding area of the substrate. In certainembodiments, the area of the film corresponds to a die on a front sideof the substrate. The film is deposited to a standard depth of betweenabout 40 nanometers and about 120 nanometers.

In other embodiments, the method 200 further includes locatingdistortions in the substrate, and compensating for the distortions byflattening the substrate. In some embodiments, the substrate may beflattened through the use of an electrostatic chuck, a Bernoulli chuck,or a vacuum chuck.

The method 200 may also include additional operations for treating thebackside of the substrate to compensate for strains on the front side ofthe substrate. In one embodiment, the method 100 may include the localdensification of the films on the backside of the substrate. Localdensification may include locally annealing or heating the substrate ina specific area to achieve a thickness reduction in the film. Thedensification may result in an increasing refractive index. Thedensification of the substrate upon high temperature annealing may alsoimpact the electrical properties of the substrate. Annealing may furtherresult in film densification which may be prominent above thecrystallization temperature. Any change in the film properties after ahigh temperature annealing process may be independent of the depositiontechnique.

In another embodiment, the method 200 may also include the localizedetching of stressed films and/or the performance of a localized reactionbetween the film and the backside of the substrate. The operation ofperforming the localized reaction between the film and the substrate maycreate a solid product of density, thermal expansion coefficient, orother property which is different than the substrate. Furthermore, ametal film may be deposited on the substrate at a temperature whichmakes the metal film compress. After the depositing, metals, such as ametal silicide material, may be subsequently deposited on the backsideof the substrate. In some embodiments, a silicon nitride material may bedeposited on the substrate. Oxygen and/or nitrogen may further be addedto the backside of the substrate, followed by a local heating, a localimplanting, and/or a local annealing operation. In another embodiment,after providing an oxide to the backside of the substrate, an ALDoperation may be performed thereon to form a ceramic layer.

In another embodiment, the method 200 may also include the localizeddeposition of films which have a different CTE than the substrate. Inorder to take advantage of the CTE difference, the difference in stressbetween the surface of the substrate may be measured and/or controlledvia the temperature at which the depositions are made. For example,depositions made at low temperatures, such as approximately 300 degreesCelsius, may be subsequently relaxed to 100 degrees Celsius. Thedifferent CTE of the film and the substrate results in different thermalexpansions and contractions between the film or films and the substrate,which may create stresses in the substrate and/or the films across theinterface between the substrate and the films.

In another embodiment, the method 200 may also include performing alocalized reaction between the film and the substrate, thus creating asolid product having a density different than a density of thesubstrate. In some embodiments, a metal film may be deposited on thebackside of the substrate at a temperature which places a compressive ortensile force upon the metal film. Subsequently oxygen and/or nitrogenmay be added to the backside of the substrate, and, in some embodiments,an additional metal material may be added thereon. Furthermore, in someembodiments, the backside of the substrate may be locally heated,locally implanted, and/or annealed.

In another embodiment, the method 200 may also include the localizedetching of the backside of the substrate to alter the geometry affectingthe stresses thereon. The localized etching may create increase ordecrease a thickness of the matter disposed on the backside of thesubstrate, thus increasing or decreasing the stress on the substrate.

In another embodiment, the method 200 may also include annealing thebackside of the substrate to change the crystal structure, crystalorientation, and/or degree of crystallinity. In some embodiments, and byway of example only, if the crystal structure and/or orientationcomprises non-isotropic crystals, the crystal orientation may be alteredby heating the substrate in a strong electromagnetic field.

Finally, the notion of depositing as described above should beunderstood to include film formations on the backside of the substratewherein the backside of the substrate obtains a different compositionvia, by way of example only, surface reactions with gases likenitridation and/or oxidation, and/or surface implantation, among othertechniques.

FIG. 3 illustrates an apparatus for processing substrates. The apparatusof FIG. 3 may be a plasma deposition chamber for depositing a film onthe backside of the substrate, as described supra.

FIG. 3 shows a schematic cross-sectional view of a chamber 300 definingtwo processing regions 318, 320. Chamber body 302 includes sidewall 312,interior wall 314, and bottom wall 316 which define two processingregions 318, 320. The bottom wall 316 in each processing region 318, 320defines at least two passages 322, 324 through which a stem 326 of apedestal heater 328 and a rod 330 of a substrate lift pin assembly aredisposed, respectively.

The sidewall 312 and the interior wall 314 define two cylindricalannular processing regions 318, 320. A circumferential pumping channel325 is formed in the chamber walls defining the cylindrical processingregions 318, 320 for exhausting gases from the processing regions 318,320 and controlling the pressure within each region 318, 320. A chamberliner or insert 327, preferably made of ceramic or the like, is disposedin each processing region 318, 320 to define the lateral boundary ofeach processing region and to protect the chamber walls 312, 314 fromthe corrosive processing environment and to maintain an electricallyisolated plasma environment between the electrodes. The liner 327 issupported in the chamber on a ledge 329 formed in the walls 312, 314 ofeach processing region 318, 320. The liner includes a plurality ofexhaust ports 331, or circumferential slots, disposed therethrough andin communication with the pumping channel 325 formed in the chamberwalls. In one embodiment, there are about twenty four ports 331 disposedthrough each line 327 which are spaces apart by about 15 degrees andlocated about the periphery of the processing regions 318, 320. Whiletwenty four ports disclosed, any number can be employed to achieve thedesired pumping rate and uniformity. In addition to the number of ports,the height of the ports relative to the face plate of the gasdistribution system is controlled to provide an optimal gas flow patternover the substrate during processing.

In some embodiments, the chamber 300 comprises a substrate edge support380. The substrate edge support 380 may be a continuous or discontinuouswall or a plurality of posts for supporting an edge portion of asubstrate above the pedestal heater 328. In some embodiments, thesubstrate edge support 380 may prevent direct contact between the deviceside of a substrate and the pedestal heater 328 to allow for depositionof a layer on the backside of the substrate.

As described supra, in some embodiments an edge support 380 may beutilized for supporting an edge portion of the substrate above apedestal heater. However, in some embodiments, the substrate may besupported by a plurality of pins. The plurality of pins may contact thesubstrate at any location on the substrate, including at a location nearthe edge of the substrate. Pin support may allow for flash heating ofthe bottom stress film side of the substrate. Furthermore, in someembodiments, a backside of the substrate may be laser annealed or heatedwith the substrate resting and/or supported on an edge of the substrate.

FIG. 4 is a plan view of a system 400 for thermally processing asubstrate. The system 400 may be utilized to apply pulsed laserradiation to substrates, as described supra. Specifically, the system400 may be utilized in a nanosecond annealing process. Furthermore, thesystem 400 may be utilized for annealing the backside of the substrate,as described supra.

The system 400 comprises an energy module 402 that has a plurality ofpulsed laser sources producing a plurality of pulsed laser pulses, apulse control module 404 that combines individual pulsed laser pulsesinto combination pulsed laser pulses, and that controls intensity,frequency characteristics, and polarity characteristics of thecombination pulsed laser pulses, a pulse shaping module 406 that adjuststhe temporal profile of the pulses of the combined pulsed laser pulses,a homogenizer 408 that adjusts the spatial energy distribution of thepulses, overlapping the combination pulsed laser pulses into a singleuniform energy field, an aperture member 416 that removes residual edgenon-uniformity from the energy field, and an alignment module 418 thatallows precision alignment of the laser energy field with a substratedisposed on a substrate support 410. A controller 412 is coupled to theenergy module 402 to control production of the laser pulses, the pulsecontrol module 404 to control pulse characteristics, and the substratesupport 410 to control movement of the substrate with respect to theenergy field. An enclosure 414 typically encloses the operativecomponents of the system 400. In some embodiments, the system 400further comprises a shadow ring 490 for shielding an edge of thesubstrate from high thermal stresses.

The substrate support 410 may feature an edge support substantiallysimilar to the edge support 380 described above in connection with FIG.3, for a similar purpose. As the stage is moved to position thesubstrate for processing specific target zones, unwanted movement of thesubstrate on the edge support may be minimized by adopting a suitablysmall spacing between the substrate edge and the shadow ring 490. Forexample, if the substrate is a 300 mm substrate, the shadow ring 490 mayhave an internal radius of 150.2 mm or less.

As described supra, in some embodiments an edge support may be utilizedfor supporting an edge portion of the substrate. However, in someembodiments, the substrate may be supported by a plurality of pins. Theplurality of pins may contact the substrate at any location on thesubstrate, including at a location near the edge of the substrate. Pinsupport may allow for pulsed laser processing of the bottom stress filmside of the substrate. Furthermore, in some embodiments, a backside ofthe substrate may be laser processed or heated with the substrateresting and/or supported on an edge of the substrate.

The lasers may be any type of laser capable of forming short pulses, forexample duration less than about 100 nsec., of high power laserradiation. Typically, high modality lasers having over 500 spatial modeswith M² greater than about 30 are used. Solid state lasers such asNd:YAG, Nd:glass, titanium-sapphire, or other rare earth doped crystallasers are frequently used, but gas lasers such as excimer lasers, forexample XeCl₂, ArF, or KrF lasers, may be used. The lasers may beswitched, for example by q-switching (passive or active), gainswitching, or mode locking. A Pockels cell may also be used proximatethe output of a laser to form pulses by interrupting a beam emitted bythe laser. In general, lasers usable for pulsed laser processing arecapable of producing pulses of laser radiation having energy contentbetween about 100 mJ and about 10 J with duration between about 1 nsecand about 100 μsec, typically about 1 J in about 8 nsec. The lasers mayhave wavelength between about 200 nm and about 2,000 nm, such as betweenabout 400 nm and about 1,000 nm, for example about 532 nm. In oneembodiment, the lasers are q-switched frequency-doubled Nd:YAG lasers.The lasers may all operate at the same wavelength, or one or more of thelasers may operate at different wavelengths from the other lasers in theenergy module 402. The lasers may be amplified to develop the powerlevels desired. In most cases, the amplification medium will be the sameor similar composition to the lasing medium. Each individual laser pulseis usually amplified by itself, but in some embodiments, all laserpulses may be amplified after combining.

A typical laser pulse delivered to a substrate is a combination ofmultiple laser pulses. The multiple pulses are generated at controlledtimes and in controlled relationship to each other such that, whencombined, a single pulse of laser radiation results that has acontrolled temporal and spatial energy profile, with a controlled energyrise, duration, and decay, and a controlled spatial distribution ofenergy non-uniformity. The controller 412 may have a pulse generator,for example an electronic timer coupled to a voltage source, that iscoupled to each laser, for example each switch of each laser, to controlgeneration of pulses from each laser.

The plurality of lasers are arranged so that each laser produces pulsesthat emerge into the pulse control module 404, which may have one ormore pulse controllers 405. One or more pulses exit the pulse controlmodule 404 and enter the pulse shaping module 406, which has one or morepulse shapers 407.

In some embodiments, the laser radiation may be directed from below thesubstrate support 410 toward the substrate, which is restingdevice-side-up on the edge support. A window or opening in the substratesupport 410 may be provided to admit laser radiation from below thesubstrate support 410 toward the backside of the substrate.

FIG. 5 is a schematic diagram of a system 500 for thermally processing asubstrate. The system 500 may be utilized to anneal, via lamp annealing,and/or chemically flash anneal substrates, as described supra.Furthermore, the system 500 may be utilized for annealing the backsideof the substrate, as described supra.

FIG. 5 is a simplified isometric view of one embodiment of a rapidthermal processing (RTP) chamber 500. An example of a rapid thermalprocessing chamber that may be adapted to benefit from the disclosure isthe VULCAN® chamber, commercially available from Applied Materials,Inc., located in Santa Clara, Calif. The processing chamber 500 includesa contactless or magnetically levitated substrate support 504, a chamberbody 502, having walls 508, a bottom 510, and a top 512 defining aninterior volume 520. The walls 508 typically include at least onesubstrate access port 548 to facilitate entry and egress of a substrate540 (a portion of which is shown in FIG. 5). The access port may becoupled to a transfer chamber (not shown) or a load lock chamber (notshown) and may be selectively sealed with a valve, such as a slit valve(not shown). In one embodiment, the substrate support 504 is annular andthe chamber 500 includes a radiant heat source 506 disposed in an insidediameter of the substrate support 504.

The substrate support 504 is adapted to magnetically levitate and rotatewithin the interior volume 520. The substrate support 504 is capable ofrotating while raising and lowering vertically during processing, andmay also be raised or lowered without rotation before, during, or afterprocessing. This magnetic levitation and/or magnetic rotation preventsor minimizes particle generation due to the absence or reduction ofmoving parts typically used to raise/lower and/or rotate the substratesupport.

The chamber 500 also includes a window 514 made from a materialtransparent to heat and light of various wavelengths, which may includelight in the infra-red (IR) spectrum, through which photons from theradiant heat source 506 may heat the substrate 540. The window 514 mayinclude a plurality of lift pins 544 coupled to an upper surface of thewindow 514, which are adapted to selectively contact and support thesubstrate 540, to facilitate transfer of the substrate into and out ofthe chamber 500.

In one embodiment, the radiant heat source 506 includes a lamp assemblyformed from a housing which includes a plurality of honeycomb tubes 560in a coolant assembly (not shown) coupled to a coolant source 583. Thecoolant source 583 may be one or a combination of water, ethyleneglycol, nitrogen (N₂), and helium (He). The housing may be made of acopper material or other suitable material having suitable coolantchannels formed therein for flow of the coolant from the coolant source583. Each tube 560 may contain a reflector and a high-intensity lampassembly or an IR emitter from which is formed a honeycomb-like pipearrangement. Dynamic control of the heating of the substrate 540 may beeffected by the one or more temperature sensors 517 (described in moredetail below) adapted to measure the temperature across the substrate540.

A stator assembly 518 circumscribes the walls 508 of the chamber body502 and is coupled to one or more actuator assemblies 522 that controlthe elevation of the stator assembly 518 along the exterior of thechamber body 502.

An atmosphere control system 564 is also coupled to the interior volume520 of the chamber body 502. The atmosphere control system 564 generallyincludes throttle valves and vacuum pumps for controlling chamberpressure. The atmosphere control system 564 may additionally include gassources for providing process or other gases to the interior volume 520.The atmosphere control system 564 may also be adapted to deliver processgases for thermal deposition processes.

The chamber 500 also includes a controller 524, which generally includesa central processing unit (CPU) 530, support circuits 528 and memory526. The CPU 530 may be one of any form of computer processor that canbe used in an industrial setting for controlling various actions andsub-processors. The memory 526, or computer-readable medium, may be oneor more of readily available memory such as random access memory (RAM),read only memory (ROM), floppy disk, hard disk, or any other form ofdigital storage, local or remote, and is typically coupled to the CPU530. The support circuits 528 are coupled to the CPU 530 for supportingthe controller 524 in a conventional manner. These circuits includecache, power supplies, clock circuits, input/output circuitry,subsystems, and the like.

The chamber 500 also includes one or more sensors 516, which aregenerally adapted to detect the elevation of the substrate support 504(or substrate 540) within the interior volume 520 of the chamber body502. The sensors 516 may be coupled to the chamber body 502 and/or otherportions of the processing chamber 500 and are adapted to provide anoutput indicative of the distance between the substrate support 504 andthe top 512 and/or bottom 510 of the chamber body 502, and may alsodetect misalignment of the substrate support 504 and/or substrate 540.The one or more sensors 516 are coupled to the controller 524 thatreceives the output metric from the sensors 516 and provides a signal orsignals to the one or more actuator assemblies 522 to raise or lower atleast a portion of the substrate support 504. The one or more sensors516 may be ultrasonic, laser, inductive, capacitive, or other type ofsensor capable of detecting the proximity of the substrate support 504within the chamber body 502.

The chamber 500 also includes one or more temperature sensors 517, whichmay be adapted to sense temperature of the substrate 540 before, during,and after processing. In the embodiment depicted in FIG. 5, thetemperature sensors 517 are disposed through the top 512, although otherlocations within and around the chamber body 502 may be used.

FIG. 6 schematically illustrates an apparatus 600 for thermallyprocessing a substrate. Specifically, the apparatus 600 may be utilizedin a millisecond annealing process. Furthermore, the system 600 may beutilized for annealing the backside of the substrate, as describedsupra.

The apparatus 600 comprises a continuous wave electromagnetic radiationmodule 601, a stage 616 configured to receive a substrate 614 thereon,and a translation mechanism 618. The continuous wave electromagneticradiation module 601 comprises a continuous wave electromagneticradiation source 602 and focusing optics 620 disposed between thecontinuous wave electromagnetic radiation source 602 and the stage 616.

The continuous wave electromagnetic radiation source 602 is capable ofemitting “continuous waves” or rays of electromagnetic radiation, suchas light. By “continuous wave” it is meant that the radiation source isconfigured to emit radiation continuously, i.e., not a burst, pulse, orflash of radiation. This is quite unlike lasers used in laser annealing,which typically use a burst or flash of light.

Furthermore, as the continuous wave electromagnetic radiation needs tobe absorbed at or near the surface of the substrate, the radiation has awavelength within the range at which the substrate absorbs radiation. Inthe case of a silicon substrate, the continuous wave electromagneticradiation preferably has a wavelength between 190 nm and 950 nm. Morepreferably, it has a wavelength of approximately 810 nm.

Alternatively, a high power continuous wave electromagnetic radiationlaser source operation in or near the UV may be used. Wavelengthsproduced by such continuous wave electromagnetic radiation laser sourcesare strongly absorbed by most otherwise reflective materials.

In a preferred embodiment, the continuous wave electromagnetic radiationsource 602 is capable of emitting radiation continuously for at least 15seconds. Also, in a preferred embodiment, the continuous waveelectromagnetic radiation source 602 comprises multiple laser diodes,each of which produces uniform and spatially coherent light at the samewavelength. The power of the laser diode(s) is in the range of 0.5 kW to50 kW, but preferably approximately 5 kW. Suitable laser diodes are madeby Coherent Inc. of Santa Clara, Calif. Spectra-Physics of California;or by Cutting Edge Optronics, Inc. of St. Charles, Mo. A preferred laserdiode is made by Cutting Edge Optronics, although another suitable laserdiode is Spectra Physics' MONSOON® multi-bar module (MBM), whichprovides 40-480 watts of continuous wave power per laser diode module.

The focusing optics 620 preferably comprise one or more collimators 606to collimate radiation 604 from the continuous wave electromagneticradiation source 602 into a substantially parallel beam 608. Thiscollimated radiation 608 is then focused by at least one lens 610 into aline of radiation 622 at an upper surface 624 of the substrate 614.

Lens 610 is any suitable lens, or series of lenses, capable of focusingradiation into a line. In a preferred embodiment, lens 610 is acylindrical lens. Alternatively, lens 610 may be one or more concavelenses, convex lenses, plane mirrors, concave mirrors, convex mirrors,refractive lenses, diffractive lenses, Fresnel lenses, gradient indexlenses, or the like.

The stage 616 may include a platform for translating the substrate, asexplained below. The stage 616 may include an edge support similar tothe edge support 390 of FIG. 3 for backside processing of the substrate.

As described supra, in some embodiments an edge support may be utilizedfor supporting an edge portion of the substrate. However, in someembodiments, the substrate may be supported by a plurality of pins. Theplurality of pins may contact the substrate at any location on thesubstrate, including at a location near the edge of the substrate. Pinsupport may allow for thermal processing of the bottom stress film sideof the substrate. Furthermore, in some embodiments, a backside of thesubstrate may be thermally processed with the substrate resting and/orsupported on an edge of the substrate.

The apparatus 600 also comprises a translation mechanism 618 configuredto translate the stage 616 and the line of radiation 622 relative to oneanother. In one embodiment, the translation mechanism 618 is coupled tothe stage 616 to move the stage 616 relative to the continuous waveelectromagnetic radiation source 602 and/or the focusing optics 620. Inanother embodiment, the translation mechanism is coupled to both thecontinuous wave electromagnetic radiation source 602 and the focusingoptics 620 to move the continuous wave electromagnetic radiation source602 and/or the focusing optics 620 relative to the stage 616. In yetanother embodiment, the translation mechanism 618 moves the continuouswave electromagnetic radiation source 602, the focusing optics 620, andthe stage 616. Any suitable translation mechanism may be used, such as aconveyor system, rack and pinion system, or the like.

In certain embodiments, the apparatus 600 comprises a shadow ring 690for shielding an edge of the substrate 614 from high thermal stresses.As noted above, the shadow ring 690 may be sized to prevent unwantedmovement of the substrate on the stage 616.

FIG. 7 illustrates a schematic diagram of an etch reactor 700. The etchreactor 700 may be utilized to etch the backside of the substrate, asdescribed supra.

In certain embodiments, the etch reactor 700 may include an ion radicalshield 770. Suitable reactors that may be adapted for use with theteachings disclosed herein include, for example, the Decoupled PlasmaSource (DPS®) II reactor, or the Tetra™ Photomask etch systems, all ofwhich are available from Applied Materials, Inc. of Santa Clara, Calif.The DPS® II reactor may also be used as a processing module of aCentura® integrated semiconductor wafer processing system, alsoavailable from Applied Materials, Inc. The particular embodiment of thereactor 700 shown herein is provided for illustrative purposes andshould not be used to limit the scope of the disclosure.

The reactor 700 generally comprises a process chamber 702 having asubstrate pedestal 724 within a conductive body (wall) 704, and acontroller 746. The chamber 702 has a substantially flat dielectricceiling 708. Other modifications of the chamber 702 may have other typesof ceilings, e.g., a dome-shaped ceiling. An antenna 710 is disposedabove the ceiling 708. The antenna 710 comprises one or more inductivecoil elements that may be selectively controlled (two co-axial elements710 a and 710 b are shown in FIG. 7). The antenna 710 is coupled througha first matching network 714 to a plasma power source 712. The plasmapower source 712 is typically capable of producing up to about 3000 W ata tunable frequency in a range from about 50 kHz to about 13.56 MHz.

The substrate pedestal (cathode) 724 is coupled through a secondmatching network 742 to a biasing power source 740. The biasing source740 generally is a source of up to about 500 W at a frequency ofapproximately 13.56 MHz that is capable of producing either continuousor pulsed power. Alternatively, the source 740 may be a DC or pulsed DCsource.

In one embodiment, the substrate support pedestal 724 provides substrateedge support. In one embodiment, the substrate support pedestal 724comprises an electrostatic chuck 760. The electrostatic chuck 760comprises at least one clamping electrode 732 and is controlled by achuck power supply 766. In alternative embodiments, the substratepedestal 724 may comprise substrate retention mechanisms such as asusceptor clamp ring, a mechanical chuck, and the like.

A reticle adapter 782 is used to secure the substrate (reticle) 722 ontothe substrate support pedestal 724. The reticle adapter 782 generallyincludes a lower portion 784 milled to cover an upper surface of thepedestal 724 (for example, the electrostatic chuck 760) and a topportion 786 having an opening 788 that is sized and shaped to hold thesubstrate 722. The opening 788 is generally substantially centered withrespect to the pedestal 724. The adapter 782 is generally formed from asingle piece of etch resistant, high temperature resistant material suchas polyimide ceramic or quartz. A suitable reticle adapter is disclosedin U.S. Pat. No. 6,251,217, issued on Jun. 26, 2001, which isincorporated herein by reference to the extent not inconsistent withaspects and claims of the disclosure. An edge ring 726 may cover and/orsecure the adapter 782 to the pedestal 724.

A lift mechanism 738 is used to lower or raise the adapter 782, andhence, the substrate 722, onto or off of the substrate support pedestal724. Generally, the lift mechanism 762 comprises a plurality of liftpins 730 (one lift pin is shown) that travel through respective guideholes 736.

In operation, the temperature of the substrate 722 is controlled bystabilizing the temperature of the substrate pedestal 724. In oneembodiment, the substrate support pedestal 724 comprises a resistiveheater 744 and a heat sink 728. The resistive heater 744 generallycomprises at least one heating element 734 and is regulated by a heaterpower supply 768. A backside gas (e.g., helium (He)) from a gas source756 is provided via a gas conduit 758 to channels that are formed in thepedestal surface under the substrate 722. The backside gas is used tofacilitate heat transfer between the pedestal 724 and the substrate 722.During processing, the pedestal 724 may be heated by the embeddedresistive heater 744 to a steady-state temperature, which in combinationwith the helium backside gas, facilitates uniform heating of thesubstrate 722. Using such thermal control, the substrate 722 may bemaintained at a temperature between about 0 and 350 degrees Celsius.

An ion-radical shield 770 is disposed in the chamber 702 above thepedestal 724. The ion-radical shield 770 is electrically isolated fromthe chamber walls 704 and the pedestal 724 and generally comprises asubstantially flat plate 772 and a plurality of legs 776. The plate 772is supported in the chamber 702 above the pedestal by the legs 776. Theplate 772 defines one or more openings (apertures) 774 that define adesired open area in the surface of the plate 772. The open area of theion-radical shield 770 controls the quantity of ions that pass from aplasma formed in an upper process volume 778 of the process chamber 702to a lower process volume 780 located between the ion-radical shield 770and the substrate 722. The greater the open area, the more ions can passthrough the ion-radical shield 770. As such, the size of the apertures774 control the ion density in volume 780. Consequently, the shield 770is an ion filter.

FIG. 8 illustrates a top schematic view of a cluster tool 810 havingmultiple substrate processing chambers 812 mounted thereon. A clustertool similar to that shown in FIG. 8 is commercially available fromApplied Materials, Inc. of Santa Clara, Calif. The cluster tool 810 maybe utilized to as a transfer chamber for transferring a substratebetween the various tools and chambers described herein.

The tool includes a loadlock chamber 820 and a transfer chamber 818having a substrate handling module 816 for moving the substrates fromlocation to location within the system, in particular, between themultiple substrate processing chambers 812. This particular tool isshown to accommodate up to four substrate processing chambers 812positioned radially about the transfer chamber, however it iscontemplated that any number of substrate processing chamber 812 may beaccommodated thereon.

Benefits of the present disclosure include processing of the bottom ofthe substrate is less likely to affect the top structures of thesubstrate thermally (e.g., via the use of surface heating techniques,high surface irradiance lasers, or flashlamps) or compositionally.Additionally, strains from the bottom of the substrate are moreconsistent as they are isolated from any processing on the top of thesubstrate. Furthermore, additional adjustments may be made on the bottomof the substrate to compensate for strains developed in laterprocessing. Once heated, implantation on the backside of the substratecounteracts other thermal stresses on the front side of the substrate.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A substrate processing method, comprising:forming device structures on a device side of a substrate comprising aplurality of dies; locating distortions in the substrate; depositing ametal containing film on a backside of the substrate, wherein thebackside of the substrate is opposite the device side; after depositingthe metal containing film, depositing a metal silicide material on thebackside of the substrate; after the depositing a metal silicidematerial, incorporating a dopant into the backside of the substrate;etching the backside of the substrate to create strains which compensatefor the distortions; aligning the substrate for patterning; andflattening the substrate.
 2. The method of claim 1, wherein the dopantis oxygen.
 3. The method of claim 2, further comprising: performing anatomic layer deposition process to form a ceramic material layer on thebackside of the substrate.
 4. The method of claim 1, wherein the dopantis nitrogen.
 5. The method of claim 1, wherein the incorporating adopant further comprises: locally implanting the dopant into thebackside of the substrate.
 6. The method of claim 1, wherein theincorporating a dopant further comprises: depositing a dopant containingfilm on the backside of the substrate and locally annealing the dopantcontaining film to create strains which compensate for the distortions.7. The method of claim 1, wherein the depositing a metal containing filmand the depositing a metal silicide material are performed at atemperature of less than about 300° C.
 8. The method of claim 1, whereinthe flattening the substrate further comprises: flattening distortionson the device side of the substrate by securing the substrate on anelectrostatic chuck.
 9. The method of claim 1, wherein the flatteningthe substrate further comprises: flattening distortions on the deviceside of the substrate by securing the substrate on a Bernoulli chuck.10. The method of claim 1, wherein the flattening the substrate furthercomprises: flattening distortions on the device side of the substrate bysecuring the substrate on a vacuum chuck.
 11. The method of claim 1,further comprising: after the incorporating a dopant into the backsideof the substrate, depositing a metal material on the backside of thesubstrate.
 12. A substrate processing method, comprising: forming devicestructures on a device side of a substrate comprising a plurality ofdies; locating distortions in the substrate; depositing a metalcontaining film on a backside of the substrate, wherein the backside ofthe substrate is opposite the device side; after depositing the metalcontaining film, depositing a silicon nitride material on the backsideof the substrate; after the depositing a silicon nitride material,incorporating a dopant into the backside of the substrate; etching thebackside of the substrate; aligning the substrate for patterning; andcompensating for the distortions by flattening the substrate.
 13. Themethod of claim 12, wherein the dopant is oxygen.
 14. The method ofclaim 13, further comprising: performing at atomic layer depositionprocess to form a ceramic material layer on the backside of thesubstrate.
 15. The method of claim 12, wherein the dopant is nitrogen.16. The method of claim 12, wherein the incorporating a dopant furthercomprises: locally implanting the dopant into the backside of thesubstrate.
 17. The method of claim 12, wherein the incorporating adopant further comprises: depositing a dopant containing film on thebackside of the substrate and locally annealing the dopant containingfilm.
 18. A substrate processing method, comprising: forming devicestructures on a device side of a substrate comprising a plurality ofdies; locating distortions in the substrate; depositing a first metalcontaining material on a backside of the substrate, wherein the backsideof the substrate is opposite the device side; after depositing the firstmetal containing material, depositing a second metal containing materialon the backside of the substrate; after the depositing a second metalcontaining material, incorporating a dopant into the backside of thesubstrate; after the depositing a second metal containing material,depositing a third metal containing material on the backside of thesubstrate; annealing the backside of the substrate to create strainswhich compensate for the distortions; and etching the backside of thesubstrate to create strains which compensate for the distortions. 19.The method of claim 18, wherein the incorporating a dopant into thebackside of the substrate comprises doping oxygen or nitrogen into thebackside of the substrate.
 20. The method of claim 18, wherein theannealing the backside of the substrate comprises localized laserannealing.